No no – no worries, I am not going anywhere. This is about the first curtain/second curtain setting you have on your flash/camera combination.

First curtain sync means:

1. the flash fires a preflash to measure the scene
2. the shutter opens
3. the flash fires
4. wait…. the shutter stays open for its designated time
5. the shutter closes

That gives you this, where the student at the School of Imaging class I taught last night is moving to our left in this slow shutter speed flash shot:

Odd. She is moving to our left? Then why is the trail off to the left? Simple – because the flash fired at the beginning of the long shutter speed.

Second curtain sync means:

1. the flash fires a preflash to measure the scene
2. the shutter opens
3. wait…. the shutter stays open for its designated time
4. the flash fires
5. the shutter closes

So now the flash fires at the end. That gives you this, a much more natural looking light trail:

So now you know what that does. And no – this does not in any way make the light softer, or the backgrounds better, or anything like that.